Sonarr/Radarr strip special characters from search requests, which has been a long-standing issue since this causes many search results to be missed if series titles contain special characters.
Apparently this has been fixed by an extra capability, but when sonarr sends queries to nzbhydra2, it still strips specials characters, so maybe nzbhydra2 is not reporting that capability (not sure how that works exactly, maybe you have further knowledge).
Sonarr/Radarr strip special characters from search requests, which has been a long-standing issue since this causes many search results to be missed if series titles contain special characters. Apparently this has been fixed by an extra capability, but when sonarr sends queries to nzbhydra2, it still strips specials characters, so maybe nzbhydra2 is not reporting that capability (not sure how that works exactly, maybe you have further knowledge).
Related issues: https://github.com/Sonarr/Sonarr/issues/1225 https://github.com/Radarr/Radarr/issues/4502